If you are using LNAV to fly a non RNAV procedure of any kind then legaly you must monitor the prescribed nav aids on which the procedure is based.
Be very careful accepting advice on what you can or cannot do, as these regs are very different in different parts of the world. What is legal in EU may not apply in the mid or far east or other areas.
As I said in an earlier post, there is no standard method of implementation so beware!!!!!